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Cytosolic pH regulation in mouse macrophages. Proton extrusion by plasma-membrane-localized H(+)-ATPase.

ABSTRACT: Recent evidence indicates that H+ extrusion in macrophages is in part accomplished by a H(+)-ATPase of vacuolar type. The presence and plasma-membrane localization of such a mechanism in adherent resident macrophages was verified by inhibition of H+ extrusion, monitored by changes in both cytosolic pH (pHi) and extracellular pH, with low concentrations of the H(+)-ATPase inhibitors N-ethylmaleimide and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole. The H(+)-ATPase was operative at physiological pHi levels, thus contributing to maintenance of steady-state pHi. It was further shown to be sensitive to the plasma-membrane potential, with hyperpolarization being strongly inhibitory. In addition, H+ extrusion mediated by the H(+)-ATPase and the generation and release of lactic acid caused acidification of the pericellular space and could enable secreted lysosomal hydrolases to act extracellularly.

SUBMITTER: Tapper H

PROVIDER: S-EPMC1130668 | biostudies-other | 1992 Jan

REPOSITORIES: biostudies-other

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Vesicular ATPase inserted into the plasma membrane of motor terminals by exocytosis alkalinizes cytosolic pH and facilitates endocytosis.

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